Thaindian News

WASHINGTON, D.C. (BNO NEWS) — The American Psychological Association (APA) on Monday announced that a recently published test shows that mental decline in elderly people is less than previously thought.

According to the results of the report published in the July issue of Neuropsychology, the mental abilities of younger adults still rose over time, but not nearly as much. And the mental abilities of older adults still fell over time, but not quite as much.

That finding contradicts data gathered by the other major research approach to aging, cross-sectional studies, which compare the performance of different age groups at the same time.

With both methods subject to bias, “It remains important to recognize the limitations of each type of study design when interpreting results,” said study author Timothy Salthouse, PhD, a fellow of the APA and other scientific associations.

Salthouse, a past winner of the APA’s William James Award, reviewed how different research methods have led to different findings. Cross-sectional studies that compared the abilities of younger and older adults showed big drops in key areas, while longitudinal studies suggested that, until about age 60, abilities are stable or even improve.

The study analyzed data on five key cognitive abilities from the longitudinal Virginia Cognitive Aging Project. Scores were available for 1,616 adults age 18 to more than 80 on tests of reasoning, spatial visualization, episodic memory, perceptual speed and vocabulary. The data were collected over an average test-retest interval of two-and-a-half years.

Participants were grouped into age brackets by decade, each with well more than 100 participants, except for the 80-89 bracket, with 87 participants.

Salthouse then estimated the size of practice effects by comparing scores earned on the second test by the longitudinal participants with scores on a first test by another group of participants. He also used statistical methods to adjust for the chance that weaker performers dropped out between the first and second tests.

In general, practice effects were evident, allowing test-takers to score higher the second time around not because they truly were more able, but because they knew the test.

However, Salthouse removed the practice-related “bonus points” to reflect more accurately normal mental aging in healthy adults.

Salthouse also found that practice effects played a bigger role in younger than older adults, possibly because younger people learn better.

“Longitudinal comparisons in people of different ages may be even more complicated because the amount of longitudinal change may be partially determined by the individual’s learning ability at a given age,” he stated.